Throughout human history foodstuffs such as grains, nuts, and the like have been ground into meal and flour by means of grinding stones. Typically, the material to be ground is placed between a set of grinding stones which are then moved, i.e., rotated, with respect to each other to effect grinding. Traditionally, grinding stones were rotated by means of wind, water, or animal power.
More recently, electric and hydraulic motors have replaced the traditional power sources. Also, at least in some cases, metal plates having very high hardness have replaced stones for use in grinding foodstuffs. Notwithstanding these and other advances, problems in establishing and maintaining precise alignment between relatively moving grinding members continue to characterize most grinding apparatus.
Traditional systems for establishing and maintaining relative positioning between grinding members have been trial and error in nature. Typically, the grinding members are initially positioned relative to one another, after which the spacing and alignment between the grinding members is checked using feeler gauges, etc. At this point shims are employed to correct deficiencies in positioning and alignment of the grinding members, after which the feeler gauges are again employed to check the results. This procedure is continued until the best possible precision in the spacing and alignment is achieved.
Unfortunately, the initial alignment of the grinding members, achieved through painstaking trial and error procedures, does not assure proper alignment of the grinding members after grinding operations commence. The introduction of material to be ground into the space between the grinding members imposes significant forces on the grinding members tending to distort the alignment therebetween, both as to spacing and as to parallelism. In such event further trial and error procedures are necessary in order to achieve alignment of the grinding members during the grinding process. It will therefore be understood that substantial improvements in the art are indicated in order to simplify the process for achieving alignment of the grinding members of a grinding apparatus and for assuring continuing alignment of the grinding members during grinding operations.
The present invention comprises a grinding apparatus for foodstuffs which fulfills the foregoing and other requirements long since found lacking in the prior art. In accordance with the broader aspects of the invention, a driven grinding member is positioned at one end of a shaft which is rotatably supported in spaced apart bearings. A sprocket is positioned between the bearings for actuation to rotate the driven grinding member about the axis of the shaft. Apparatus is provided at the opposite end of the shaft for positioning the driven grinding member in accordance with the requirements of particular grinding operations.
The driven grinding member is positioned within a grinding chamber in a precisely spaced apart relationship to a fixed grinding member. The fixed grinding member is rigidly secured to a door which is in turn rigidly securable to the grinding chamber housing. Structure is provided for pivoting the fixed grinding member about vertical and horizontal axes in order to assure precise parallelism between the driven and fixed grinding members.
The door also supports an input mechanism for delivering foodstuffs to be ground into the space between the driven and fixed grinding members. The input mechanism includes a hopper for receiving foodstuffs to be ground and an auger for transferring the foodstuffs from the hopper through the fixed grinding member and into the space between the fixed grinding member and the driven grinding member. The driven grinding member is provided with a distributing blade which causes foodstuffs received from the auger to move outwardly thereby eliminating the necessity of providing a foodstuff delivery auger having sufficient power to force the foodstuffs outwardly between the fixed and driven grinding members. Grinding chamber clearing members are mounted on the driven grinding member for rotation therewith.